A memory device including a plurality of memory cells, a peripheral circuit, and control logic. The peripheral circuit is configured to generate a plurality of operating voltages used in a memory operation, based on a target pump clock, and perform the memory operation by using the plurality of operating voltages. The control logic is configured to select the target pump clock among a plurality of pump clocks, based on a number of data bits which selected memory cells on which the memory operation is to be performed among the plurality of memory cells store, and control the peripheral circuit to perform the memory operation on the selected memory cells.